Table of Content

10 April 2011, Volume 22 Issue 7

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Space Trajectory Analysis and Parameter Selection on Large Spherical Precision Grinding

HOU Hai-Yun, JIANG Tian-Yi, HU De-Jin

2011, 22(7):  757-761,766. 

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To meet the requirements in research and development on the grinding machine of large spherical workpieces whose diameters are as high as 2 meters, this paper established a mathematical model based on the machining principles. In order to make sure space trajectories would not coincide in multiple machining, regularity of distribution on the beginning and end points was researched and the basic relationship of process parameters was obtained. A series of analyses of parameter selection strategies on large spherical precision grinding were done to enhance the density and uniformity of distribution of space trajectories. An experiment based on different grinding parameters demonstrates that a group of appropriate parameter values have an obvious effect on the surface roughness.

Study on Axial Deformation of Ball Screw

LI Ling-Feng, LIU Cai-Fen

2011, 22(7):  762-766. 

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Based on the current elastic deformation theory of single-nut ball screw, a model of ball screw was developed and a modified formula of axial deformation of ball screw was derived. Based on a given ball screw, the effects of each parameter on the axial deformation and driving performance of single-nut ball screw were analyzed. The study shows that the axial deformation can be decreased and driving performance can be improved by adopting proper parameters. Then a simplified finite element model of ball screw was established and the contact analysis and axial deformation analysis was conducted by FEA. At last, the results were compared with ones that were solved by the theoretical model above.

Study on Vibrating EDM of Deep Micro-hole on High Resistance Silicon

CAO Yin-Feng, LIU Zhi-Dong, QIU Meng-Bei, TIAN Zong-Jun, HUANG Yin-Hui

2011, 22(7):  767-771. 

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Micro-hole EDM technology on high resistance semiconductor silicon was carried out herein. Through attaching mechanical vibration to a piece of silicon, the efficiency of perforation under the conditions of different amplitudes and frequencies was studied. Experiments show that with the larger amplitude, EDM efficiency first increases and then reduces; as the frequency becomes larger, the efficiency of perforation improves gradually. The reasons are that:the larger amplitude, the better the chip removal, the lower the short-circuit rate, the higher the discharge rate. However, when the amplitude is greater than the discharge gap, the silicon hits with the tool electrode directly, the discharge rate declines. On the other hand, the larger the frequency, the higher the pulse utilization rate. At last, a hole whose diameter is 0.3mm and the ratio of depth to diameter is 25.3 and a equilateral triangle hole whose side is 0.9mm were achieved on P-type silicon whose resistivity is 2.1Ω · cm.

Analysis of Natural Vibration Localization of Random Mistuned Bladed Disk with Grouped Blades

WANG Ai-Lun, SUN Bo-Hai

2011, 22(7):  771-775. 

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Based on the lumped parameter model of a bladed disk with grouped blades, sensitivity of natural frequency and modal shape to random mistuning were analyzed by using Monte Carlo simulation method, and the connection between mistuning strength and sensitivity of vibration localization to random mistuning was also investigated. The simulation results show that natural frequency is insensitive to random mistuning, but in the closely spaced modal region, modal shape is much sensitive to random mistuning, and minor change of standard deviation of natural frequency reflects the sensitivity of blades modal localization to random mistuning. Furthermore, the sensitivity increases with increasing random mistuning strength, but it maintains at a relatively stable state when mistuning strength reaches to a high level.

Experimental Research on Influences of Oil Supply Pressure Fluctuations on Control Precision of Rolling Mill Screwing Down

CHEN Chun-Meng, WANG Yi-Qun, YANG Yang, CHEN Gang, HAN Song-Sha

2011, 22(7):  776-780. 

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In an electro-hydraulic servo controlled cylinder system, the hydraulic automatic gauge control system for a rolling mill is for complexity,heavy load,disturbance factors,strong coupling,high control precision and fast response speed. Constant pressure energy source system made up of constant pressure pump, accumulator,control valve and connecting pipe was used to provide stable pressure,adequate flow and clean working medium.In a simulation model of the rolling mill,the supply oil pressure was usually set to be as constant,while fluctuating pressure.The pressure fluctuation on the quality of rolled products has not been released in the form of paper, so far.Simulation model of supply energy source-the hydraulic automatic gauge control system was established; by experiments, the relationship among accumulators before valve and output characteristics of energy source,fluctuating supply pressure and system control precision,fluctuating supply pressure and product quality，were analyzed.That improves precision of control system and provides the basis for product quality.

Fatigue Life Analysis for Auto Frame Based on Modal Stress Recovery

JIAN Li-Jun, TUN Dao-Dun, CHU An-Ding, ZHANG Kuo

2011, 22(7):  780-784. 

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A fatigue analysis method based on MSR was presented and applied to predict the life of a frame. The finite element modal analysis of frame was performed in the software MSC.Nastran. Secondly, the whole vehicle rigid-flexible coupling model equipped with the frame as a flexible component was built and analyzed in ADAMS/Car Ride to obtain the modal displacement histories through driving on strengthen-road. Then the stress histories of the frame were got by MSR. The life distribution of the frame and the fatigue lives of the most damaged points were obtained. The results are in accordance with those of road tests，and this method is valid to evaluate car-body structure fatigue life at product design stage conveniently.

Accuracy Reliability Research of Transmission System for Numerical Control Machines

SONG Jiang-Bei, LIU Hong-Zhao, YUAN Da-Ning, TUN Zi-Yang, WANG Jian-Beng

2011, 22(7):  785-789. 

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In order to improve the accuracy reliability of a transmission system for numerical control machines,this paper established basic models of accuracy reliability of the transmission system for the machine and researched the main factors which could influence transmission accuracy for the numerical control machines,based on the theory of mechanical precision design and mechanical reliability design.The main factors affecting the transmission accuracy were sorted,using sensitivity design theory to find the weak links of the accuracy reliability.A double-frequency laser interferometer was applied for the accuracy reliability experiments in order to put forward countermeasures of increasing the accuracy reliability of the transmission system. Engineering applications show that the accuracy reliability design for transmission systems is closer to engineering practices.

Numerical Simulation of Deflections for Rotating Wind Turbine Blades Based on Aeroelastics and Aerodynamics

WANG Xu-Dong, CHEN Jin, WANG Li-Cun, LIU Qun-Feng

2011, 22(7):  790-793. 

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Based on the structural dynamic equations of blades, an aeroelastic model of a rotating rotor and the numerical simulation method of the deflections were presented under aerodynamic loads and centrifugal forces. Coupling the aerodynamic characteristics and the structure stress, the flapwise and edgewise loads and deflections of the rotating blades were calculated and plotted by using this model. Finally, the computation was completed for a 2MW wind turbine. The deflections of the blades under different wind speeds and different rotating time were given to validate the reliability of the model presented herein. The results have very important significance to estimate the vibration performance, fatigue life of the blades and to direct the design of high performance blades. 

Intelligent Fuel Consumption Testing Technology on Engine Based on Weight-loss Method

FU Bai-Hua, HU Qing-Hai

2011, 22(7):  793-797. 

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Aiming at the common problems of engines’ fuel-consumption measuring and testing technology, combining with the domestic and foreign research level and development trend, adopting sensing technology, single chip microcomputer(SCM) control technology and display technology, a research of intelligent fuel-consumption testing technology was made. A mathematical model of engines’ fuel-consumption testing system was established based on the testing principles;its hardware and steering circuit were designed in accordance with its functional requirements; its control procedures were programed to test petrol engine and diesel engine on the road or indoors in a steady-state and dynamic way. Through theoretical error analysis and experimental calibration, the accuracy of fuel-consumption testing can reach 0.4%.

Analysis of Sound Radiation of Two Elastic Cylindrical Enclosures Connected by Mechanical Joints

TAO Hao-Ping

2011, 22(7):  798-803. 

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A model of sound radiated from two connected cylindrical enclosures with a wide variety of boundary conditions was deduced by using Hamiltonian function and Rayleigh-Ritz method herein. By means of artifical springs along the connected points of two flexible panels, this model allowed the consideration of structural joint conditions.A general formulation considering the full coupling between the subsystems(plates,shell and cavities) was developed. Two main issues were reached. One is that the sound radiation of the enclosure structure is governed by the substructure excited directly, the other is that the rotational stiffness of connected points has less influence on the sound radiation than the translational stiffness has. The contribution and highlight of this paper are that it provides some supports in engineering theoretically.

Simulation and Experimental Research on Removal Rate Uniformity During Fixed Abrasive Polishing

KANG Jing, ZUO Dui-Wen, SUN Yu-Li, SHU Yong-Wei

2011, 22(7):  803-807. 

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In order to study removal rate uniformity, a three-dimensional stress distribution model was built using ANSYS herein. The equivalent stress distribution on the workpiece surface was got, and the influence of various factors on the removal rate uniformity was studied. To solve the uneven stress distribution, two methods were proposed: thickening the carrying device and designing a new kind of load device. By doing two groups of comparative experiments, the two methods that proposed to improve stress distribution uniformity were verified to be useful.

Research on Influence Factors on Welding Residual Stress in Ball-Pipe Joints

YUAN Zhi-Jun, FU Ming-Fu

2011, 22(7):  808-812. 

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The magnitude and the distribution of the welding residual stress of such joints were researched with FEM method considering some different influence factors, and welding residual stress near the ball will reduce along with the increase of the thickness and diameter of the ball. And the welding residual Von-Misses stress and Z component stress will increase with the pipe diameter enlargement.

Interpretation of Manson-Coffin Model of Low Cycle Fatigue Based on Damage Mechanics

ZHENG Zhan-Guang, CA Gan-Wei, LI Zhao-Jun, XU Xi-Yong

2011, 22(7):  812-814. 

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Manson-Coffin model of low cycle fatigue is a classical empirical formula, and its mechanical implications are very pool. Based on damage mechanics and Ramberg-Osgood rule, a damage mechanics model of low cycle fatigue was deduced under the dominate variable of plastic strain amplitude. By the comparison with Manson-Coffin model, it is shown that they are equivalent under proportional loading and Manson-Coffin model is a special degenerative form of damage mechanics fatigue model.

Grinding Mechanism and Key Structural Parameters of Tower Grinding Mill

MU Fu-Sheng, DONG Fang, SHI Jin-Dong, HU Bao-Yu

2011, 22(7):  815-817. 

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The grinding mechanism and the influerces of key parameters on its performance for tower grinding mill are not yet clear,the impacts of the stirrer structural parameters of a tower grinding mill on the grinding efficiency were investigated. The experimental results show the tower grinding mill grinding process consistents with Charles’s formula, and it is established the kinematics model of grinding media in the annular between the stirrer and cylinder. It shows that larger stirrer diameter is help to improve the grinding efficiency, and less helix angle of stirrer is help to increase shear power of grinding, and the grinding efficiency will be less reduced in the stirring speed above the critical speed.

Workpiece Online Identification Method Based on SVM and Power Information

HE Xiao-Hui, YAN Ping, LIU Fei, HU Shao-Hua, CHEN Guo-Rong

2011, 22(7):  818-824. 

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In order to solve the problem that the workpiece machining progress information mainly relied on manual statistics incurring frequent errors in case of mixed category machining, a kind of workpiece online identification method based on SVM algorithm and power information was proposed. At first, through analyzing characteristics of spindle power variation during machining process of workpiece, a group of power curve time domain statistical features, and machining power characteristic parameters were selected to constitute characteristic vector for identifying workpiece. Then characteristic vector samples of various workpieces waiting to be processed were acquired by trial machining, and these vector samples were trained to build up classifiers, which were related to a type of workpiece respectively. During identification stage, characteristic vector of workpiece under machining should be extracted in real time and then compared with each classifier. According to the value of decision-making function, the type of workpiece shall be identified. The test results show that the identification method is of good robustness and generalization and its performance is superior to BP neural network and a template matching algorithm.

Capacity Planning for Mixed Production Line Based on Directed Weighted Networks

YANG Ting, ZHANG Ding-Hua, CHEN Bing, LI Shan

2011, 22(7):  824-829. 

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Facing to capacity planning for mixed production line which is a complicated problem, a directed weighted network was constructed to describe the complex processing relationships among working stations. Anyway the stability of mixed production line is the most important problem for capacity planning. Therefore the whole status and the key vertices should be obtained by means of topological characteristics of network architecture. And then the capacity redundancy and resources configuration will be planned in order to avoid the catastrophic failure of the whole production line due to accidental disable of vertices. Finally, an actual production was introduced as an example. According to the small-world property shown in the network, the capacity is planned through controlling the working load of those vertices with high degree.

A Self-evolution Algorithm for Scheduling a Flow-shop-like Knowledgeable Manufacturing Cell

LI Wen-Chao, YAN Hong-Sen

2011, 22(7):  830-835. 

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The flow-shop-like knowledgeable manufacturing cell (whose machine number is greater than 2) scheduling is a NP-complete problem and has not a completely valid algorithm for it until now. A self-evolution algorithm with learning ability was proposed according to its structure and characteristics. By adopting the value iterative strategies of reinforcement learning, the algorithm can absorb the corresponding knowledge from its environment during its running and improve its search ability. The approximation of value function is completed by use of the SVM with a hybrid kernel to avoid the too many states in learning process. Numerical experiments show that the algorithm has excellent performance of learning and evolution for the problem.

Study on Weak Mechanical Vibration Feature Extraction from Mixed Signal Including Noise

MA Chao, ZHANG Lin-Ke, LV Zhi-Jiang, DAN Yong

2011, 22(7):  836-839. 

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For monitoring vibration, the signals acquired from sensors are the mixture of vibration signal of machines and the environmental noise. The blind source separation can extract the feature signals of each machine from the mixed signals. A blind source separation algorithm was proposed herein to extract the feature signal in the presence of the environmental noise. The experimental investigation of extraction of the feature signal from mechanical vibration signals mixed with environmental noise was carried out, and the results show that the algorithm can eliminate the influence of environmental noise and extract the weak signals of the machine. 

Study on Substrate Temperature Data Fusion for Large-area Diamond Film

HONG Hong-Bei

2011, 22(7):  839-842,859. 

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Considering the measurement with requirements of high precision and stability for large area diamond film substrate temperature, the necessity of multi-branch measuring data fusion was analyzed. Different data fusion methods were utilized to carry out the data fusion research of sampled substrate temperature data. The robustness of data fusion method was analyzed in details. The research results demonstrate that multi-branch substrate temperature data fusion for large area diamond film can reflect the actual substrate temperature more truly, and the fusion results are with high precision; when temperature measurement is affected by non-normal disturbances or even by sensors’ breakdown, the data fusion results can still be with high precision, and the performance of rejecting disturbance and sensors’ breakdown is improved significantly.

Study on Influence of Cell-structures on Contact Strength of Thick-walled Cellular Materials

JIE Fang, LIU Zuo-Min

2011, 22(7):  843-847. 

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Materials of H59 brass were chosen for the preparation of cylindrical specimens which contained single pore with different structures, and YE-600 hydraulic pressure testing machine was used for compression tests on these specimens. The influences of the porosity, the shape of the pore and the load-bearing direction on the contact strength of the materials were discussed. Research results show that: the increase of porosity leads to the decrease of contact strength of the material, and its contact strength is markedly effected by the pore-structures. The contact strength of the material with regular hexagon pore is superior to the material with round hole, and the contact strength of the load to-edge is higher than that of the load in diagonal. Cracks are generated in the edge of micropore which is the nearest away from the initial point of contact and expandes along the direction which is parallel to the load. It is indicated by the contrast between experiments and finite element analysis that the contact failure of the thick-walled cellular materials is caused by the largest principal stretching stress. 

Research on Multi-step Active Disassembly Methods and Design Principles of Products Based on ADSM

DIAO Liu-Xian, LIU Zhi-Feng, LI Xin-Yu, ZHANG Hong-Chao, CHENG Huan-Bei

2011, 22(7):  848-852. 

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It is difficult to disassemble the complicated or big product completely, it is also difficult to choose the components if they are mixed together. One of the solutions is multi-step active disassembly. This paper mainly studied a method of multi-step active disassembly, discussed the theory, and analyzed the design principles of multi-step active disassembly products. Finally, the feasibility of multi-step active disassembly was proven by using actual example.

Product Configuration Design Method Based on Performance Simulation

AI Hui, CHEN Li-Beng, LI Yu-Mei, XIONG Ben-Fan

2011, 22(7):  853-859. 

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In order to quickly respond to customer requirements in complex product development, a rapid design method based on the integration of multidisciplinary collaborative configuration and performance simulation was proposed. In the presented method, product scheme was generated rapidly by configuration reasoning based on product family model integrated multi-domain knowledge，and the product performance prediction was achieved by simulation of Modelica language based multi-domain simulation model that was established automatically by mapping transform. The multi-domain knowledge expressed by characteristic parameters and constraints was fused into the product family model, and the process of configuration reasoning and performance simulation were presented. Finally, the feasibility of the method was verified on a developed manipulator family.

Research on Reduction of Residual Vibration for Trajectory Glue Based on Pulse Reshape Filter

SHI Wei-Min, YANG Liang-Liang, DAO Wei, WU Chuan-Yu

2011, 22(7):  860-863. 

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In order to realize the automatization of sole glue working procedure,an auto-glue toe lasting machine was developed, but it is a high flexible machine and easy to produce residual vibration because of its structure. The existence of residual vibration degrades tracking precision and response speed of trajectory glue and influences the quality of trajectory glue and following procedure. This paper used pulse reshape filer in discrete domain, designed and optimized input command reshaper against the system vibration mode, filtered the input command and eliminated the residual vibration, improved system response. Experiments show pulse reshape filter is effective against residual vibration caused by high flexible mode of auto-glue toe lasting machine.

Dynamic Model on AFS Headlamp Swiveling Angle

DENG Liang, CHEN Bao-Xue, ZHANG Jian-Ban, GU Dong-Chao, SUN Hai-Chao

2011, 22(7):  864-869. 

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According to the control strategy that headlamp illuminating area should cover safety distance on curving road, this paper proposed that four wheels steering model and ABS braking model can calculate headlamp swiveling angle, as inputs of vehicle speed and front wheel steering angle. By the comparison of simulations based on Matlab/Simulink with experiments of the designed control and testing system based on LabVIEW programs by centripetal acceleration sensor, it was testified effectively. 

Design Modeling and Simulation of Three Oil Port Variable Axial Piston Pump with Paralleled Kidney Slot

ZHONG Wei-Xu, QUAN Long

2011, 22(7):  869-872. 

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In order to compensate for the area deviation of differential cylinder and change the output flow of the pump, a program of parallel-type of three-window of variable axial piston pump was proposed. The new typital piston pump can output two flows, and can be used to balance the asymmetric flow of differential cylinder in closed-loop system, achieving the desired effect of single-pump controlling differential cylinder.First a geometric model of the piston pump was established based on the Pro/E software,then against the problem of crossing angle at the new valve plate’s damping trough and the characteristics of new pump’s flow output ,a simulation model of controling the pump’s displacement was established based on the AMEsim simulation software. The authors compared the impact of the flow of piston pump caused by the crossing angle of new valve plate's damping trough, determined reasonable design parameters of the valve plate, analyzed the wave characteristics of pump’s flow output and the control characteristics of pump’s variable displacement.The research work makes a guiding role in designing and manufacturing new variable axial piston pump

Automobile Style Design Method Based on Three Dimensional Sketch

JIANG Chao, GU Zheng-Qi, YANG Yi, HE Yi-Bin

2011, 22(7):  873-877. 

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To solve the problem that how to integrate aesthetics and aerodynamics in car style design,a good performance aerodynamical ideal shape can be used as a reference,by projecting art element design on its feature line,a three dimensional sketch used for aesthetics evaluation can be made,when the sketch was finalized,the CAD model used for aesthetics render and numerical control machining can be directly modeled. According to this idea,a new conceptual sports car was chosen as an example, by wind tunnel test,this idea can fulfil the requests for art style and aerodynamics in car style design. 

Optimization Design of Powertrain Mounting System Based on Improved Genetic Simulated Annealing Algorithm

HU Wen-Qing, CHEN Jian

2011, 22(7):  878-881. 

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Owing to merits and demerits of genetic algorithm and simulated annealing algorithm, the two algorithms were combined. As the probabilities of crossover and mutation were dynamically adopted to overcome the premature phenomenon of genetic algorithm, A improved genetic simulated annealing algorithm was formed and used in the optimization of powertrain mounting system.